1. Technical Field
The present invention relates to a damper, particularly to a damper with micro-nano fluid.
2. Related Art
The function of the conventional damper is for shock absorbing, deceleration, and energy dissipation. When an object moves, no matter linearly or rotatably, impact can be generated. The impact can directly or indirectly cause damage to the object. By installing the damper, the impact can be avoided or minimized, or the mechanical energy generated by the impact can be absorbed.
Most of the conventional dampers in the market are passive vibration dampers, which can be classified as Viscous Damper, Viscoelastic Dampers, Frictional Dampers, and Metal Dampers, etc. Each kind of dampers minimizes the impact caused by vibrating in a way of metal yielding of the damper itself, or by the viscous force of liquid or a solid.
The fluid damper using viscous force of liquid to minimize the impact caused by vibration mainly includes a hollow tubular shell filled with a working fluid, and a piston movably installed in the shell. The moving speed of the piston can be slowed down by providing damping force to the piston from the working fluid.
Another kind of damper reduces the impact by actively controlled vibration. By providing energy to the damper, the damping force and viscosity of the damper can be varied. The advantage of this kind of damper lies in that timely and effectively controlling the action of the damper by providing extra energy to the damper. However, active control consumes a lot of energy, and this kind of damper will also be out of function due to power failure. Therefore, a semi-active damper which only needs very little energy to change the material characteristic of the damper draws public attention and is under research. These kind of dampers, such as Magnetorheological Dampers, Electrorheological Dampers, etc., use magnetic field or electric field to change the arrangement of the micro-nano particle inside the damper to further change the viscosity of the fluid, thereby changing the relation of the damping force, the velocity, and the arrearage of the loop area, or using micro energy switch gate system to change the whole mechanical characteristic of the damper. However, changing the way the damper works by adjusting the electricity still has the problems of durability, voltage life and cost. In the long term, the passive controlling system will be safer and more stable considering the maintenance cost and the risk of malfunction of the electrical equipment.
The semi-active controlling damper needs to use additional electric and magnetic device, and also other related structure arranged on the damper. Therefore, the cost of this kind of damper is higher than other kinds of damper. Moreover, the electric/magnetic field generated by the electromagnetic device of the damper is not easy to be evenly distributed, and the arrangement of iron particle is not easy to be controlled either. Thus, the partial damping force of the damper cannot be controlled accurately, which further influences the damper to show the expected result.
Fluid Viscous Damper (FVD) is formed in tubular piston shape, and the hydraulic cylinder is filled with viscous fluid which flows from one side of the damper via the gap between the piston plate and the sleeve to the other side of the damper. By the characteristic that damping force is proportional to the flow velocity when the fluid flows, energy generated during the moving of the object can be absorbed by the damping force generated from the pressure difference between two sides of the piston.
The characteristic of the linear viscous damper is that when the viscosity of the fluid is higher, the damping force of the damper will become larger. The energy that the damper consumes will be transformed into thermal energy. Thus, when the temperature of the fluid rises, the viscosity of the fluid gets low.
The conventional damper structure has ball bearings installed on the piston head to reduce friction between the piston head and the interior surfaces of the tube, thereby improving the lifetime of the damper and lowering the repairing frequency. Moreover, when the piston is pushed by the pressure differences between two sides of the piston, the flow opening between the piston head and the tube sleeve can be adjusted to regulate the damping force of the damper, and the user can also control the controlling rod to adjust the relative position of the throttling element and the pushing rod. By doing so, the damping force of the damper can be regulated.
However, except the improvement of the piston and the sleeve related elements, the fluid characteristic for the whole system can also be an important influential factor. The damper system will have higher wear and damping force if using high polymer material with high viscosity, so the fluid damper in a whole still has room for improvement.